/*
   This example code is in the Public Domain (or CC0 licensed, at your option.)

   Unless required by applicable law or agreed to in writing, this
   software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
   CONDITIONS OF ANY KIND, either express or implied.
*/
#include <string.h>
#include <freertos/FreeRTOS.h>
#include <freertos/task.h>
#include <freertos/event_groups.h>
#include <esp_wifi.h>
#include <esp_event.h>
#include <esp_log.h>
#include <esp_idf_version.h>
#include <esp_netif.h>

#include <network_provisioning/manager.h>
#ifdef CONFIG_APP_NETWORK_PROV_TRANSPORT_BLE
#include <network_provisioning/scheme_ble.h>
#else /* CONFIG_APP_NETWORK_PROV_TRANSPORT_SOFTAP */
#include <network_provisioning/scheme_softap.h>
#include <hap_platform_httpd.h>
#endif /* CONFIG_APP_NETWORK_PROV_TRANSPORT_BLE */
#ifdef CONFIG_APP_NETWORK_PROV_SHOW_QR
#include <qrcode.h>
#endif
#include <nvs.h>
#include <nvs_flash.h>
#include <esp_timer.h>
#include "app_wifi_with_homekit.h"

ESP_EVENT_DEFINE_BASE(APP_WIFI_EVENT);
#ifdef CONFIG_APP_NETWORK_USE_WAC_PROVISIONING
#include <hap_wac.h>
#endif /* CONFIG_APP_NETWORK_USE_WAC_PROVISIONING */

static const char *TAG = "app_wifi";
static const int WIFI_CONNECTED_EVENT = BIT0;
static EventGroupHandle_t wifi_event_group;

#define PROV_QR_VERSION "v1"

#define PROV_TRANSPORT_SOFTAP   "softap"
#define PROV_TRANSPORT_BLE      "ble"
#define QRCODE_BASE_URL     "https://rainmaker.espressif.com/qrcode.html"

#define CREDENTIALS_NAMESPACE   "rmaker_creds"
#define RANDOM_NVS_KEY          "random"

#define POP_STR_SIZE    9
static esp_timer_handle_t prov_stop_timer;
/* Timeout period in minutes */
#define APP_NETWORK_PROV_TIMEOUT_PERIOD   CONFIG_APP_NETWORK_PROV_TIMEOUT_PERIOD
/* Autofetch period in micro-seconds */
static uint64_t prov_timeout_period = (APP_NETWORK_PROV_TIMEOUT_PERIOD * 60 * 1000000LL);

#if ESP_IDF_VERSION >= ESP_IDF_VERSION_VAL(5, 1, 3)
#define APP_PROV_STOP_ON_CREDS_MISMATCH
#elif (CONFIG_APP_NETWORK_PROV_MAX_RETRY_CNT > 0)
#warning "Provisioning window stop on max credentials failures, needs IDF version >= 5.1.3"
#endif

#ifdef CONFIG_APP_NETWORK_PROV_SHOW_QR
static esp_err_t qrcode_display(const char *text)
{
#define MAX_QRCODE_VERSION 5
    esp_qrcode_config_t cfg = ESP_QRCODE_CONFIG_DEFAULT();
    cfg.max_qrcode_version = MAX_QRCODE_VERSION;
    return esp_qrcode_generate(&cfg, text);
}
#endif

static void app_wifi_print_qr(const char *name, const char *pop, const char *transport)
{
    if (!name || !transport) {
        ESP_LOGW(TAG, "Cannot generate QR code payload. Data missing.");
        return;
    }
    char payload[150];
    if (pop) {
        snprintf(payload, sizeof(payload), "{\"ver\":\"%s\",\"name\":\"%s\"" \
                ",\"pop\":\"%s\",\"transport\":\"%s\"}",
                PROV_QR_VERSION, name, pop, transport);
    } else {
        snprintf(payload, sizeof(payload), "{\"ver\":\"%s\",\"name\":\"%s\"" \
                ",\"transport\":\"%s\"}",
                PROV_QR_VERSION, name, transport);
    }
#ifdef CONFIG_APP_NETWORK_PROV_SHOW_QR
    printf("Scan this QR code from the phone app for Provisioning.\n");
    qrcode_display(payload);
#endif /* CONFIG_APP_NETWORK_PROV_SHOW_QR */
    printf("If QR code is not visible, copy paste the below URL in a browser.\n%s?data=%s\n", QRCODE_BASE_URL, payload);
    esp_event_post(APP_WIFI_EVENT, APP_WIFI_EVENT_QR_DISPLAY, payload, strlen(payload) + 1, portMAX_DELAY);
}

#ifdef CONFIG_APP_NETWORK_USE_WAC_PROVISIONING
#ifdef CONFIG_APP_NETWORK_PROV_TRANSPORT_SOFTAP
static void app_wac_softap_start(char *ssid)
{
}
#else
static void app_wac_softap_start(char *ssid)
{
    hap_wifi_softap_start(ssid);
}
#endif /* ! CONFIG_APP_NETWORK_PROV_TRANSPORT_SOFTAP */
static void app_wac_softap_stop(void)
{
    hap_wifi_softap_stop();
}
static void app_wac_sta_connect(wifi_config_t *wifi_cfg)
{
    network_prov_mgr_configure_sta(wifi_cfg);
}
#endif /* CONFIG_APP_NETWORK_USE_WAC_PROVISIONING */


/* Event handler for catching system events */
static void event_handler(void* arg, esp_event_base_t event_base,
                          int32_t event_id, void* event_data)
{
#ifdef CONFIG_APP_NETWORK_RESET_PROV_ON_FAILURE
    static int retries = 0;
#endif
#ifdef APP_PROV_STOP_ON_CREDS_MISMATCH
    static int failed_cnt = 0;
#endif
    if (event_base == NETWORK_PROV_EVENT) {
        switch (event_id) {
            case NETWORK_PROV_START:
                ESP_LOGI(TAG, "Provisioning started");
                break;
            case NETWORK_PROV_WIFI_CRED_RECV: {
                wifi_sta_config_t *wifi_sta_cfg = (wifi_sta_config_t *)event_data;
                ESP_LOGI(TAG, "Received Wi-Fi credentials"
                         "\n\tSSID     : %s\n\tPassword : %s",
                         (const char *) wifi_sta_cfg->ssid,
                         (const char *) wifi_sta_cfg->password);
                break;
            }
            case NETWORK_PROV_WIFI_CRED_FAIL: {
                network_prov_wifi_sta_fail_reason_t *reason = (network_prov_wifi_sta_fail_reason_t *)event_data;
                ESP_LOGE(TAG, "Provisioning failed!\n\tReason : %s"
                         "\n\tPlease reset to factory and retry provisioning",
                         (*reason == NETWORK_PROV_WIFI_STA_AUTH_ERROR) ?
                         "Wi-Fi station authentication failed" : "Wi-Fi access-point not found");
#ifdef CONFIG_APP_NETWORK_RESET_PROV_ON_FAILURE
                retries++;
                if (retries >= CONFIG_APP_NETWORK_PROV_MAX_RETRY_CNT) {
                    ESP_LOGI(TAG, "Failed to connect with provisioned AP, reseting provisioned credentials");
                    network_prov_mgr_reset_wifi_sm_state_on_failure();
                    esp_event_post(APP_WIFI_EVENT, APP_WIFI_EVENT_PROV_RESTART, NULL, 0, portMAX_DELAY);
                    retries = 0;
                }
#endif
                break;
            }
            case NETWORK_PROV_WIFI_CRED_SUCCESS:
                ESP_LOGI(TAG, "Provisioning successful");
#ifdef CONFIG_APP_NETWORK_RESET_PROV_ON_FAILURE
                retries = 0;
#endif
                break;
            case NETWORK_PROV_END:
                if (prov_stop_timer) {
                    esp_timer_stop(prov_stop_timer);
                    esp_timer_delete(prov_stop_timer);
                    prov_stop_timer = NULL;
                }
#ifdef CONFIG_APP_NETWORK_USE_WAC_PROVISIONING
                hap_wac_stop();
#endif
                /* De-initialize manager once provisioning is finished */
                network_prov_mgr_deinit();
                break;
            default:
                break;
        }
#ifdef APP_PROV_STOP_ON_CREDS_MISMATCH
    } else if (event_base == PROTOCOMM_SECURITY_SESSION_EVENT) {
        switch (event_id) {
            case PROTOCOMM_SECURITY_SESSION_SETUP_OK:
                ESP_LOGI(TAG, "Secured session established!");
                break;
            case PROTOCOMM_SECURITY_SESSION_INVALID_SECURITY_PARAMS:
                /* fall-through */
            case PROTOCOMM_SECURITY_SESSION_CREDENTIALS_MISMATCH:
                ESP_LOGE(TAG, "Received incorrect PoP or invalid security params! event: %d", (int) event_id);
                if (CONFIG_APP_NETWORK_PROV_MAX_POP_MISMATCH &&
                        (++failed_cnt >= CONFIG_APP_NETWORK_PROV_MAX_POP_MISMATCH)) {
                    /* stop provisioning for security reasons */
                    network_prov_mgr_stop_provisioning();
                    ESP_LOGW(TAG, "Max PoP attempts reached! Provisioning disabled for security reasons. Please reboot device to restart provisioning");
                    esp_event_post(APP_WIFI_EVENT, APP_WIFI_EVENT_PROV_CRED_MISMATCH, NULL, 0, portMAX_DELAY);
                }
                break;
            default:
                break;
        }
#endif
    } else if (event_base == WIFI_EVENT && event_id == WIFI_EVENT_STA_START) {
        esp_wifi_connect();
    } else if (event_base == WIFI_EVENT && event_id == WIFI_EVENT_STA_CONNECTED) {
        esp_netif_create_ip6_linklocal((esp_netif_t *)arg);
    } else if (event_base == IP_EVENT && event_id == IP_EVENT_STA_GOT_IP) {
        ip_event_got_ip_t* event = (ip_event_got_ip_t*) event_data;
        ESP_LOGI(TAG, "Connected with IP Address:" IPSTR, IP2STR(&event->ip_info.ip));
        /* Signal main application to continue execution */
        xEventGroupSetBits(wifi_event_group, WIFI_CONNECTED_EVENT);
    } else if (event_base == IP_EVENT && event_id == IP_EVENT_GOT_IP6) {
        ip_event_got_ip6_t *event = (ip_event_got_ip6_t *)event_data;
        ESP_LOGI(TAG, "Connected with IPv6 Address:" IPV6STR, IPV62STR(event->ip6_info.ip));
    } else if (event_base == WIFI_EVENT && event_id == WIFI_EVENT_STA_DISCONNECTED) {
        ESP_LOGI(TAG, "Disconnected. Connecting to the AP again...");
        esp_wifi_connect();
#ifdef CONFIG_APP_NETWORK_USE_WAC_PROVISIONING
    } else if (event_base == HAP_WAC_EVENT) {
        switch (event_id) {
            case HAP_WAC_EVENT_REQ_SOFTAP_START:
                app_wac_softap_start((char *)event_data);
                break;
            case HAP_WAC_EVENT_REQ_SOFTAP_STOP:
                app_wac_softap_stop();
                break;
            case HAP_WAC_EVENT_RECV_CRED:
                app_wac_sta_connect((wifi_config_t *)event_data);
                break;
            case HAP_WAC_EVENT_STOPPED:
                ESP_LOGI(TAG, "WAC Stopped");
                break;
            default:
                break;
        }
#endif /* CONFIG_APP_NETWORK_USE_WAC_PROVISIONING */
    }
}

static void wifi_init_sta()
{
    ESP_ERROR_CHECK(esp_wifi_set_mode(WIFI_MODE_STA));
    ESP_ERROR_CHECK(esp_wifi_start());
}
/* Free random_bytes after use only if function returns ESP_OK */
static esp_err_t read_random_bytes_from_nvs(uint8_t **random_bytes, size_t *len)
{
    nvs_handle handle;
    esp_err_t err;
    *len = 0;

    if ((err = nvs_open_from_partition(CONFIG_ESP_RMAKER_FACTORY_PARTITION_NAME, CREDENTIALS_NAMESPACE,
                                NVS_READONLY, &handle)) != ESP_OK) {
        ESP_LOGD(TAG, "NVS open for %s %s %s failed with error %d", CONFIG_ESP_RMAKER_FACTORY_PARTITION_NAME, CREDENTIALS_NAMESPACE, RANDOM_NVS_KEY, err);
        return ESP_FAIL;
    }

    if ((err = nvs_get_blob(handle, RANDOM_NVS_KEY, NULL, len)) != ESP_OK) {
        ESP_LOGD(TAG, "Error %d. Failed to read key %s.", err, RANDOM_NVS_KEY);
        nvs_close(handle);
        return ESP_ERR_NOT_FOUND;
    }

    *random_bytes = calloc(*len, 1);
    if (*random_bytes) {
        nvs_get_blob(handle, RANDOM_NVS_KEY, *random_bytes, len);
        nvs_close(handle);
        return ESP_OK;
    }
    nvs_close(handle);
    return ESP_ERR_NO_MEM;
}

static esp_err_t get_device_service_name(char *service_name, size_t max)
{
    uint8_t *nvs_random = NULL;
    const char *ssid_prefix = CONFIG_APP_NETWORK_PROV_NAME_PREFIX;
    size_t nvs_random_size = 0;
    if ((read_random_bytes_from_nvs(&nvs_random, &nvs_random_size) != ESP_OK) || nvs_random_size < 3) {
        uint8_t eth_mac[6];
        esp_wifi_get_mac(WIFI_IF_STA, eth_mac);
        snprintf(service_name, max, "%s_%02x%02x%02x", ssid_prefix, eth_mac[3], eth_mac[4], eth_mac[5]);
    } else {
        snprintf(service_name, max, "%s_%02x%02x%02x", ssid_prefix, nvs_random[nvs_random_size - 3],
                nvs_random[nvs_random_size - 2], nvs_random[nvs_random_size - 1]);
    }
    if (nvs_random) {
        free(nvs_random);
    }
    return ESP_OK;
}


static char *get_device_pop(app_wifi_pop_type_t pop_type)
{
    if (pop_type == POP_TYPE_NONE) {
        return NULL;
    }
    char *pop = calloc(1, POP_STR_SIZE);
    if (!pop) {
        ESP_LOGE(TAG, "Failed to allocate memory for PoP.");
        return NULL;
    }

    if (pop_type == POP_TYPE_MAC) {
        uint8_t eth_mac[6];
        esp_err_t err = esp_wifi_get_mac(WIFI_IF_STA, eth_mac);
        if (err == ESP_OK) {
            snprintf(pop, POP_STR_SIZE, "%02x%02x%02x%02x", eth_mac[2], eth_mac[3], eth_mac[4], eth_mac[5]);
            return pop;
        } else {
            ESP_LOGE(TAG, "Failed to get MAC address to generate PoP.");
            goto pop_err;
        }
    } else if (pop_type == POP_TYPE_RANDOM) {
        uint8_t *nvs_random = NULL;
        size_t nvs_random_size = 0;
        if ((read_random_bytes_from_nvs(&nvs_random, &nvs_random_size) != ESP_OK) || nvs_random_size < 4) {
            ESP_LOGE(TAG, "Failed to read random bytes from NVS to generate PoP.");
            if (nvs_random) {
                free(nvs_random);
            }
            goto pop_err;
        } else {
            snprintf(pop, POP_STR_SIZE, "%02x%02x%02x%02x", nvs_random[0], nvs_random[1], nvs_random[2], nvs_random[3]);
            free(nvs_random);
            return pop;
        }
    }
pop_err:
    free(pop);
    return NULL;
}

void app_wifi_with_homekit_init(void)
{
    /* Initialize TCP/IP */
    esp_netif_init();

    /* Initialize the event loop */
    ESP_ERROR_CHECK(esp_event_loop_create_default());
    wifi_event_group = xEventGroupCreate();

    /* Initialize Wi-Fi including netif with default config */
    esp_netif_t *wifi_netif = esp_netif_create_default_wifi_sta();

    /* Register our event handler for Wi-Fi, IP and Provisioning related events */
    ESP_ERROR_CHECK(esp_event_handler_register(WIFI_EVENT, ESP_EVENT_ANY_ID, &event_handler, wifi_netif));
    ESP_ERROR_CHECK(esp_event_handler_register(NETWORK_PROV_EVENT, ESP_EVENT_ANY_ID, &event_handler, NULL));
#ifdef APP_PROV_STOP_ON_CREDS_MISMATCH
    ESP_ERROR_CHECK(esp_event_handler_register(PROTOCOMM_SECURITY_SESSION_EVENT, ESP_EVENT_ANY_ID, &event_handler, NULL));
#endif
    ESP_ERROR_CHECK(esp_event_handler_register(IP_EVENT, IP_EVENT_STA_GOT_IP, &event_handler, NULL));
    ESP_ERROR_CHECK(esp_event_handler_register(IP_EVENT, IP_EVENT_GOT_IP6, &event_handler, NULL));

    wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
    ESP_ERROR_CHECK(esp_wifi_init(&cfg));
}

static void app_wifi_prov_stop(void *priv)
{
    ESP_LOGW(TAG, "Provisioning timed out. Please reboot device to restart provisioning.");
    network_prov_mgr_stop_provisioning();
    esp_event_post(APP_WIFI_EVENT, APP_WIFI_EVENT_PROV_TIMEOUT, NULL, 0, portMAX_DELAY);
}

esp_err_t app_wifi_start_timer(void)
{
    if (prov_timeout_period == 0) {
        return ESP_OK;
    }
    esp_timer_create_args_t prov_stop_timer_conf = {
        .callback = app_wifi_prov_stop,
        .arg = NULL,
        .dispatch_method = ESP_TIMER_TASK,
        .name = "app_wifi_prov_stop_tm"
    };
    if (esp_timer_create(&prov_stop_timer_conf, &prov_stop_timer) == ESP_OK) {
        esp_timer_start_once(prov_stop_timer, prov_timeout_period);
        ESP_LOGI(TAG, "Provisioning will auto stop after %d minute(s).",
                APP_NETWORK_PROV_TIMEOUT_PERIOD);
        return ESP_OK;
    } else {
        ESP_LOGE(TAG, "Failed to create Provisioning auto stop timer.");
    }
    return ESP_FAIL;
}

esp_err_t app_wifi_with_homekit_start(app_wifi_pop_type_t pop_type)
{
    /* Configuration for the provisioning manager */
    network_prov_mgr_config_t config = {
        /* What is the Provisioning Scheme that we want ?
         * network_prov_scheme_softap or network_prov_scheme_ble */
#ifdef CONFIG_APP_NETWORK_PROV_TRANSPORT_BLE
        .scheme = network_prov_scheme_ble,
#else /* CONFIG_APP_NETWORK_PROV_TRANSPORT_SOFTAP */
        .scheme = network_prov_scheme_softap,
#endif /* CONFIG_APP_NETWORK_PROV_TRANSPORT_BLE */

        /* Any default scheme specific event handler that you would
         * like to choose. Since our example application requires
         * neither BT nor BLE, we can choose to release the associated
         * memory once provisioning is complete, or not needed
         * (in case when device is already provisioned). Choosing
         * appropriate scheme specific event handler allows the manager
         * to take care of this automatically. This can be set to
         * NETWORK_PROV_EVENT_HANDLER_NONE when using network_prov_scheme_softap*/
#ifdef CONFIG_APP_NETWORK_PROV_TRANSPORT_BLE
        .scheme_event_handler = NETWORK_PROV_SCHEME_BLE_EVENT_HANDLER_FREE_BTDM
#else /* CONFIG_APP_NETWORK_PROV_TRANSPORT_SOFTAP */
        .scheme_event_handler = NETWORK_PROV_EVENT_HANDLER_NONE,
#endif /* CONFIG_APP_NETWORK_PROV_TRANSPORT_BLE */
    };

    /* Initialize provisioning manager with the
     * configuration parameters set above */
    ESP_ERROR_CHECK(network_prov_mgr_init(config));

    bool provisioned = false;
    /* Let's find out if the device is provisioned */
    ESP_ERROR_CHECK(network_prov_mgr_is_wifi_provisioned(&provisioned));

    /* If device is not yet provisioned start provisioning service */
    if (!provisioned) {
        ESP_LOGI(TAG, "Starting provisioning");
        esp_netif_create_default_wifi_ap();
        /* What is the Device Service Name that we want
         * This translates to :
         *     - Wi-Fi SSID when scheme is network_prov_scheme_softap
         *     - device name when scheme is network_prov_scheme_ble
         */
        char service_name[12];
        get_device_service_name(service_name, sizeof(service_name));

        /* What is the service key (Wi-Fi password)
         * NULL = Open network
         * This is ignored when scheme is network_prov_scheme_ble
         */
        const char *service_key = NULL;

        /* What is the security level that we want (0 or 1):
         *      - NETWORK_PROV_SECURITY_0 is simply plain text communication.
         *      - NETWORK_PROV_SECURITY_1 is secure communication which consists of secure handshake
         *          using X25519 key exchange and proof of possession (pop) and AES-CTR
         *          for encryption/decryption of messages.
         */
        network_prov_security_t security = NETWORK_PROV_SECURITY_1;

        /* Do we want a proof-of-possession (ignored if Security 0 is selected):
         *      - this should be a string with length > 0
         *      - NULL if not used
         */
        char *pop = get_device_pop(pop_type);
        if ((pop_type != POP_TYPE_NONE) && (pop == NULL)) {
            return ESP_ERR_NO_MEM;
        }

#ifdef CONFIG_APP_NETWORK_PROV_TRANSPORT_BLE
        /* This step is only useful when scheme is network_prov_scheme_ble. This will
         * set a custom 128 bit UUID which will be included in the BLE advertisement
         * and will correspond to the primary GATT service that provides provisioning
         * endpoints as GATT characteristics. Each GATT characteristic will be
         * formed using the primary service UUID as base, with different auto assigned
         * 12th and 13th bytes (assume counting starts from 0th byte). The client side
         * applications must identify the endpoints by reading the User Characteristic
         * Description descriptor (0x2901) for each characteristic, which contains the
         * endpoint name of the characteristic */
        uint8_t custom_service_uuid[] = {
            /* This is a random uuid. This can be modified if you want to change the BLE uuid. */
            /* 12th and 13th bit will be replaced by internal bits. */
            0xb4, 0xdf, 0x5a, 0x1c, 0x3f, 0x6b, 0xf4, 0xbf,
            0xea, 0x4a, 0x82, 0x03, 0x04, 0x90, 0x1a, 0x02,
        };
        esp_err_t err = network_prov_scheme_ble_set_service_uuid(custom_service_uuid);
        if (err != ESP_OK) {
            ESP_LOGE(TAG, "network_prov_scheme_ble_set_service_uuid failed %d", err);
            return err;
        }
#endif /* CONFIG_APP_NETWORK_PROV_TRANSPORT_BLE */


#ifdef CONFIG_APP_NETWORK_PROV_TRANSPORT_SOFTAP
        network_prov_scheme_softap_set_httpd_handle(hap_platform_httpd_get_handle());
#endif /* CONFIG_APP_NETWORK_PROV_TRANSPORT_SOFTAP */

        /* Start provisioning service */
        ESP_ERROR_CHECK(network_prov_mgr_start_provisioning(security, pop, service_name, service_key));
        /* Print QR code for provisioning */
#ifdef CONFIG_APP_NETWORK_PROV_TRANSPORT_BLE
        app_wifi_print_qr(service_name, pop, PROV_TRANSPORT_BLE);
#else /* CONFIG_APP_NETWORK_PROV_TRANSPORT_SOFTAP */
        app_wifi_print_qr(service_name, pop, PROV_TRANSPORT_SOFTAP);
#endif /* CONFIG_APP_NETWORK_PROV_TRANSPORT_BLE */
        ESP_LOGI(TAG, "Provisioning Started. Name : %s, POP : %s", service_name, pop ? pop : "<null>");
        app_wifi_start_timer();
#ifdef CONFIG_APP_NETWORK_USE_WAC_PROVISIONING
        esp_event_handler_register(HAP_WAC_EVENT, ESP_EVENT_ANY_ID, &event_handler, NULL);
        if (pop) {
            free(pop);
        }
        hap_wac_start();
#endif /* CONFIG_APP_NETWORK_USE_WAC_PROVISIONING */
    } else {
        ESP_LOGI(TAG, "Already provisioned, starting Wi-Fi STA");

        /* We don't need the manager as device is already provisioned,
         * so let's release it's resources */
        network_prov_mgr_deinit();

        /* Start Wi-Fi station */
        wifi_init_sta();
    }
    /* Wait for Wi-Fi connection */
    xEventGroupWaitBits(wifi_event_group, WIFI_CONNECTED_EVENT, false, true, portMAX_DELAY);
    return ESP_OK;
}
